User:Dora Gustafson/llAxes2Rot right and wrong

To see if it really matters this demands on unit vectors and orthogonality, I made a test script to satisfy my own curiosity: <lsl> key model; integer tog=0; vector lookat;

rotation Vec2RotBastard( vector V ) {

   vector UP = < 0.0, 0.0, 1.0 >;
   vector LEFT = llVecNorm(UP%V);
   return llAxes2Rot(V, LEFT, UP);
   // demand for orthogonal, unit vectors is not fulfilled in general:
   // V is a unit vector in special cases only
   // UP and V are orthogonal in special cases only

}

rotation Vec2RotNorm( vector V ) {

   V = llVecNorm( V );
   vector UP = < 0.0, 0.0, 1.0 >;
   vector LEFT = llVecNorm(UP%V);
   return llAxes2Rot(V, LEFT, UP);
   // demand for orthogonal vectors is not fulfilled in general:
   // UP and V are orthogonal in special cases only

}

rotation Vec2RotTrue( vector V ) {

   V = llVecNorm( V );
   vector UP = < 0.0, 0.0, 1.0 >;
   vector LEFT = llVecNorm(UP%V);
   UP = llVecNorm(V%LEFT); // you want to keep the direction of V
   return llAxes2Rot(V, LEFT, UP);

}

rotation Vec2RotHor( vector V ) {

   V = llVecNorm( V );
   vector UP = < 0.0, 0.0, 1.0 >;
   vector LEFT = llVecNorm(UP%V);
   V = llVecNorm(LEFT%UP); // you want V confined to the horizontal plane
   return llAxes2Rot(V, LEFT, UP);

}

default {

   touch_end(integer n)
   {
       llSetTimerEvent( 4.0 );
       model = llDetectedKey(0);
   }

   timer()
   {
       lookat = llList2Vector( llGetObjectDetails( model, [OBJECT_POS]), 0 );
       if ( lookat != ZERO_VECTOR )
       {
           if ( !tog )
           {
               llSetColor ( <1.0, 0.2, 0.0>, ALL_SIDES );
               llSetRot( Vec2RotBastard( lookat - llGetPos()));
           }
           else if ( tog == 1 )
           {
               llSetColor ( <1.0, 1.0, 0.0>, ALL_SIDES );
               llSetRot( Vec2RotNorm( lookat - llGetPos()));
           }
           else if ( tog == 2 )
           {
               llSetColor ( <0.4, 1.0, 0.0>, ALL_SIDES );
               llSetRot( Vec2RotTrue( lookat - llGetPos()));
           }
           else if ( tog == 3 )
           {
               llSetColor ( <0.0, 0.6, 1.0>, ALL_SIDES );
               llSetRot( Vec2RotHor( lookat - llGetPos()));
           }
           tog = ++tog % 4;
       }
       else
       {
           llSetColor ( <0.0, 0.0, 0.0>, ALL_SIDES );
           llSetTimerEvent( 0.0 );
       }
   }

} </lsl> How to use: rezz a prim say x,y,z = 5.0, 0.2, 0.2 meters, put he script in and touch the prim. It will point you for 4 sec with each routine in turn. Move around and fly up to see where the prim will point. Each routine will color the prim its own color: Red: "Bastard" routine. Yellow: "Norm" routine, unit vectors but not orthogonal. Green: "True" routine, true direction. Blue: "Hor" routine, direction in the horizontal plane only.